Intake valve vent means



Dec. 23, 1958 M. H. FRANK INTAKE VALVE VENT MEANS Filed Feb. 19, 1958 INVENTOR. dZ/aimf ATTORNEY United States Patent 2,865,354 INTAKE VALVEVENT MEANS Mark H.- Frank, Birmingham, Mich., assignor to General MotorsCorporation, Detroit, Mich., a corporation of Delaware ApplicationFebruary 19, 1958, Serial No. 716,215 Claims. (Cl. 123-90) Thisinvention relates to means for preventing the flow of fluids betweenseparate chambers having different pressure conditions therein and hasparticular application to engines having valve guide means extendedwithin induction passages wherein the pressure differential between theends of such guide means causes lubricant to flow into the enginesinduction system.

This invention is a continuation-in-part of both of the copendingapplications Serial Number 513,295 entitled Intake Valve Vent Means,filed June 6, 1955, now abandoned, and Serial Number 566,512 entitledValve Guide Vent Means, filed February 20, 1956, now abandoned, bothfiled in the name of this same inventor. In overhead valve engineshaving valve guide means extending from the rocker arm chamber to withinthe intake manifold, at engine conditions causing a high intake manifoldsuction, lubricant is drawn through the guide means from the rocker armchamber and is inducted into the combustion chambers of the engine whereit is burned and lost.

It is here proposed to provide improved valve guide vent means whichwill reduce the pressure differential between the ends of the valveguiding means and prevent the loss of lubricant heretofore experienced.It is proposed to have the reciprocal valve stem member, or the guidemeans, formed to include an elongated annular groove and to have suchgroove in continuous communication with atmospheric venting means,during the reciprocal travel thereof.

In the drawings:

Figure 1 is a fragmentary section of an engine, cut away and havingparts shown in cross-section to illustrate the present invention.

Figure 2 is an enlarged cross-sectional view of the proposed atmosphericvalve guide vent means.

Figure 3 is a cross-sectional view of the proposed vent means taken fromFigure 2 in the plane of line 3-3 and looking in the direction of thearrows thereon.

Figure 4 is a modification of the invention shown in Figure 1 showingthe proposed vent means with the groove in the valve guide.

In the drawings there is shown a fragmentary section of an overheadvalve engine including the engine block 12 and head 14. Within theengine head is provided an induction system comprising a combustionchamber 16 and intake manifold passage means 18. An overhead intakevalve 20 is extended through a Wall 21 and into the intake manifoldpassage 18, and the valve head 22 separates the intake passage 18 fromthe combustion chamber 16. The intake valve stem 24 is received within avalve stem sleeve guide 26 provided in the engine head 14. The valvestem 24 and guide 26 extend upward into a rocker arm chamber 28 which isclosed by a cover 30.

The intake valve 20 is biased by spring means 32 and is actuated by apush rod 34 through a rocker arm 36 in a conventional manner.

Piston means 38 travels within the cylinder 40 formed in the engineblock 12 and the usual spark plug means 42 is provided through the wallof the head and extended within the combustion chamber 16.

The chamber 28 receives lubricating oil in order to maintain the movableparts therewithin in proper operating condition. This space, duringengine operation, is filled with a fine mist of lubricating oil vaporswhich tend to collect on the lower walls of the chamber and members suchas the valve stem 24 and guide 26 extended therewithin. Under certainengine operating conditions, there is a high vacuum condition within theintake manifold passage 18 and at such times the pressure condition inthe intake manifold 18 is much lower than it is in the chamber 28 andthere is a tendency to draw valve stem lubricant down into the intakemanifold from where it is carried to the combustion chamber 16, burned,and lost.

To prevent the aforementioned loss of lubricating oils, the workingspace 44 between the valve stem 24 and its respective guide 26 is ventedto the atmosphere by means of a vent passage 46 provided through enginehead 14, wall 21, and guide 26. There is also provided an elongatedrecess 01' groove 50 about the valve stem 24 which communicates with thevent passage 46. The groove 50 is such in length as remains incommunication with the vent passage 46 during the full stroke of thevalve means 20; the closed position being shown by Figure 1 and the openposition by Figure 2.

Under high intake manifold vacuum conditions, the vent passage 46prevents the high suction pressure normally Within the space 44, betweenthe valve stem 24 and guide 26, from existing about the valve stem andextending into chamber 28, and consequently, eliminates the drawing ofexcess lubricant from chamber 28 through space 44, into the intakepassage.

A modification of the above-described vent means is shown in Figure 4wherein the communicating groove 52 is located in the valve stem guide54 instead of the valve stem itself. in this modification the valve stemextends through the valve guide 54 in a similar manner and the groove 52provides atmospheric pressure about the valve stem to prevent the flowof lubricant therealong.

Under normal engine operating conditions reciprocation of the valve stem24 within its guide provides a film of lubricant about the valve stem.Since there is no appreciable pressure differential between the chamberend of the valve stem passage 44 and the atmosphere end to the ventpassage 46, and what pressure difference there is exists at the intakemanifold end of the valve stem pas sage, no lubricant will be lostthrough the vent passage 46 and no lubricant will be drawn into theintake manifold, under normal operating conditions, other thanpreviously occurred. However, under high intake manifold conditions, thevalve stem passage 44 being vented to atmosphere between the chamber 28and the intake manifold 18, permits no lubricant to be drawn intopassage 44, due to the high manifold suction, other than that which isnormally occasioned by valve stem reciprocation.

I claim:

1. In an engine having intake valve stems extending through a wallseparating a lubrication space from engine induction passages andwherein the difference in the pressure condition within said inductionpassages as compared to the pressure condition within said lubricationspace produces a negative pressure condition about the ends of saidvalve stems received within said lubrication space which normallyinduces the flow of lubricant about said valve stems from saidlubrication space to said induction passages and results in thesubsequent loss thereof, atmospheric vent passages formed through theside wall of said engine and through said separating wall andterminating in open communication with each of said intake valve stemsindividually for providing an atmospheric pressure condition about saidvalve stems intermediate said lubrication space and said inductionpassages more nearly similar to the pressure condition Withinsaidlubrica'tion space and thereby substantially eliminating thenegative pressure condition about the ends ofsaid valvestems within saidlubrication space inducingrthe how and loss of lubricant to saidinduction passages.

2. An engine having a lubrication space and induction passagesprovidedtherein and dividing walls separating said lubrication space from saidinduction passages, intake valve stems journaled within said dividingwalls and extending between said lubrication space and saidinductionpassages, said engine having a negative pressure condition within saidinduction passages and about said valve stems, including the end thereofreceived within said lubrication space, normally inducing the flow oflubricant from said space torsaid passages during the operation of saidengine, and atmospheric vent passages formed through the side Wall ofsaid engine and through said dividing walls and terminating in opencommunication with each of said intake valve stems individually forproviding, an atmospheric pressure condition about said valve stemsintermediate said lubrication space and said induction passages morenearly similar to the pressure condition within said lubrication spaceand thereby substantially eliminating the negative pressure conditionabout the ends of said valve stems within said lubrication spaceinducing the flow and loss of lubricant to said induction passages.

3. An engine having a lubricating space and an induction passage, anengine Wall separating said lubricating space and said inductionpassage, a valve. stem-and a valve stem guide extending through saidengine wall and having ends terminating between said lubricating spaceand said induction passage, the difference in pressure between saidlubricating space and said induction passage producing a negativepressure condition about the end of said valve stem in said lubricatingspace and tending to induce the flow of lubricant along said valve stemfrom said lubricating space to said induction passage, and anatmospheric vent passage formed through said engine wall and said valvestem guide and terminating in open communication With said valve stemintermediate said lubricating space and said induction passage forproviding an atmospheric pressure condition about said valve stemsimilar to the pressure condition in said lubricating space andpreventing the flow of lubricant along said valve stem to said inductionpassage.

4. An engine as described in claim 3 wherein said atmospheric ventpassage communicates with an annular groove formed in said valve stem.

5. An engine as described in claim 3 wherein said atmospheric ventpassage communicates with an annular groove formed in the side wall ofsaid valve stem guide.

References Cited in the file of this patent UNITED STATES PATENTS1,712,539 Willgoos May 14, 1929 1,856,304 Whiteley May 3, 1932 2,175,261Harbaugh Oct. 10, 1939 2,598,476 Wrightrnan May 27, 1952 FOREIGN PATENTS438,836 Great Britain Nov. 25, 1935

